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Do A.H.,University of California at Irvine | Do A.H.,Long Beach Veterans Affairs Medical Center | Wang P.T.,University of California at Irvine | King C.E.,University of California at Irvine | And 2 more authors.
Journal of NeuroEngineering and Rehabilitation | Year: 2011

Background: Many neurological conditions, such as stroke, spinal cord injury, and traumatic brain injury, can cause chronic gait function impairment due to foot-drop. Current physiotherapy techniques provide only a limited degree of motor function recovery in these individuals, and therefore novel therapies are needed. Brain-computer interface (BCI) is a relatively novel technology with a potential to restore, substitute, or augment lost motor behaviors in patients with neurological injuries. Here, we describe the first successful integration of a noninvasive electroencephalogram (EEG)-based BCI with a noninvasive functional electrical stimulation (FES) system that enables the direct brain control of foot dorsiflexion in able-bodied individuals. Methods. A noninvasive EEG-based BCI system was integrated with a noninvasive FES system for foot dorsiflexion. Subjects underwent computer-cued epochs of repetitive foot dorsiflexion and idling while their EEG signals were recorded and stored for offline analysis. The analysis generated a prediction model that allowed EEG data to be analyzed and classified in real time during online BCI operation. The real-time online performance of the integrated BCI-FES system was tested in a group of five able-bodied subjects who used repetitive foot dorsiflexion to elicit BCI-FES mediated dorsiflexion of the contralateral foot. Results: Five able-bodied subjects performed 10 alternations of idling and repetitive foot dorsifiexion to trigger BCI-FES mediated dorsifiexion of the contralateral foot. The epochs of BCI-FES mediated foot dorsifiexion were highly correlated with the epochs of voluntary foot dorsifiexion (correlation coefficient ranged between 0.59 and 0.77) with latencies ranging from 1.4 sec to 3.1 sec. In addition, all subjects achieved a 100% BCI-FES response (no omissions), and one subject had a single false alarm. Conclusions: This study suggests that the integration of a noninvasive BCI with a lower-extremity FES system is feasible. With additional modifications, the proposed BCI-FES system may offer a novel and effective therapy in the neuro-rehabilitation of individuals with lower extremity paralysis due to neurological injuries. © 2011 Do et al; licensee BioMed Central Ltd.

Fuller B.E.,Portland Veterans Affairs Medical Center | Fuller B.E.,Oregon Health And Science University | Rodriguez V.L.,Portland Veterans Affairs Medical Center | Linke A.,Portland Veterans Affairs Medical Center | And 3 more authors.
General Hospital Psychiatry | Year: 2011

Objective: To assess the prevalence of three liver diseases [hepatitis C virus (HCV), nonalcoholic fatty liver disease and alcohol-induced cirrhosis] in patients (veterans) with/without schizophrenia/schizoaffective disorder and bipolar disorder. Methods: A retrospective electronic chart review of Veterans Integrated Services Network 20 facilities from January 1, 2001 to December 21, 2006 selected patients to one of two groups: schizophrenia/schizoaffective disorder or bipolar disorder. Patients in both groups were compared with veterans in an equal-sized random sample from the same data set of veterans without psychiatric diagnoses. Logistic regression models evaluated risk for overall liver diseases as well as HCV, nonalcoholic fatty liver disease and alcoholic-induced cirrhosis. Results: Patients with schizophrenia (n=6521) had a higher prevalence of liver disease [22.4% versus 3.2%; odds ratio (OR)=8.73]; HCV (16.5% versus 1.9%; OR=10.21); and alcohol-related cirrhosis (1.6% versus 0.4%; OR=4.09) than matched controls. Patients with bipolar disorder (n=5319) had a higher prevalence of liver disease (21.5% versus 3.5%; OR=7.58); HCV (15.5% versus 2.1%; OR=8.60); and alcohol-related cirrhosis (1.6% versus 0.4%; OR=3.82) than matched controls. Risk factors for liver disease in patients with schizophrenia (versus matched controls) included diabetes (OR=1.29), hypertension (OR=1.27), HIV (OR=3.54), substance use disorder (SUD) (OR=2.28), alcohol use disorder (OR=3.05) and schizophrenia (OR=2.74). Risk factors for development of liver disease for patients with bipolar disorder: diabetes (OR=1.40), HIV (OR=3.66), SUD (OR=2.68), alcohol use disorder (OR=3.22) and bipolar disorder (OR=2.27). Conclusions: This study in veterans shows that the presence of mental illness and its comorbidities represents a significant risk factor for the diagnosis of liver disease, including HCV and alcohol-related cirrhosis. © 2011.

Tehrani D.M.,University of California at Irvine | Tehrani D.M.,Long Beach Veterans Affairs Medical Center | Seto A.H.,University of California at Irvine | Seto A.H.,Long Beach Veterans Affairs Medical Center
Cleveland Clinic Journal of Medicine | Year: 2013

Updated definitions of myocardial infarction (MI) reflect research on measuring cardiac troponin to diagnose MI. Elevations of this biomarker indicate cardiac injury but not always an acute coronary syndrome. Clinical judgment is needed to interpret increasingly sensitive biomarker assays appropriately. Here, we review the new MI definitions and the various causes of elevated troponin to enable physicians to differentiate acute coronary syndromes from other conditions.

Wang P.T.,University of California at Irvine | King C.E.,University of California at Irvine | Chui L.A.,Long Beach Veterans Affairs Medical Center | Do A.H.,University of California at Irvine | And 2 more authors.
Journal of Neural Engineering | Year: 2012

Objective. Spinal cord injury (SCI) often leaves affected individuals unable to ambulate. Electroencephalogram (EEG) based brain-computer interface (BCI) controlled lower extremity prostheses may restore intuitive and able-body-like ambulation after SCI. To test its feasibility, the authors developed and tested a novel EEG-based, data-driven BCI system for intuitive and self-paced control of the ambulation of an avatar within a virtual reality environment (VRE). Approach. Eight able-bodied subjects and one with SCI underwent the following 10-min training session: subjects alternated between idling and walking kinaesthetic motor imageries (KMI) while their EEG were recorded and analysed to generate subject-specific decoding models. Subjects then performed a goal-oriented online task, repeated over five sessions, in which they utilized the KMI to control the linear ambulation of an avatar and make ten sequential stops at designated points within the VRE. Main results. The average offline training performance across subjects was 77.2±11.0%, ranging from 64.3% (p = 0.001 76) to 94.5% (p = 6.26×10-23), with chance performance being 50%. The average online performance was 8.5±1.1 (out of 10) successful stops and 303±53 s completion time (perfect = 211 s). All subjects achieved performances significantly different than those of random walk (p < 0.05) in 44 of the 45 online sessions. Significance. By using a data-driven machine learning approach to decode users' KMI, this BCI-VRE system enabled intuitive and purposeful self-paced control of ambulation after only 10 minutes training. The ability to achieve such BCI control with minimal training indicates that the implementation of future BCI-lower extremity prosthesis systems may be feasible. © 2012 IOP Publishing Ltd.

King C.E.,University of California at Irvine | Wang P.T.,University of California at Irvine | Chui L.A.,University of California at Irvine | Do A.H.,University of California at Irvine | And 2 more authors.
Journal of NeuroEngineering and Rehabilitation | Year: 2013

Background: Spinal cord injury (SCI) can leave the affected individuals with paraparesis or paraplegia, thus rendering them unable to ambulate. Since there are currently no restorative treatments for this population, novel approaches such as brain-controlled prostheses have been sought. Our recent studies show that a brain-computer interface (BCI) can be used to control ambulation within a virtual reality environment (VRE), suggesting that a BCI-controlled lower extremity prosthesis for ambulation may be feasible. However, the operability of our BCI has not yet been tested in a SCI population. Methods. Five participants with paraplegia or tetraplegia due to SCI underwent a 10-min training session in which they alternated between kinesthetic motor imagery (KMI) of idling and walking while their electroencephalogram (EEG) were recorded. Participants then performed a goal-oriented online task, where they utilized KMI to control the linear ambulation of an avatar while making 10 sequential stops at designated points within the VRE. Multiple online trials were performed in a single day, and this procedure was repeated across 5 experimental days. Results: Classification accuracy of idling and walking was estimated offline and ranged from 60.5% (p = 0.0176) to 92.3% (p = 1.36×10§ssup§-20§esup§) across participants and days. Offline analysis revealed that the activation of mid-frontal areas mostly in the μ and low β bands was the most consistent feature for differentiating between idling and walking KMI. In the online task, participants achieved an average performance of 7.4±2.3 successful stops in 273±51 sec. These performances were purposeful, i.e. significantly different from the random walk Monte Carlo simulations (p<0.01), and all but one participant achieved purposeful control within the first day of the experiments. Finally, all participants were able to maintain purposeful control throughout the study, and their online performances improved over time. Conclusions: The results of this study demonstrate that SCI participants can purposefully operate a self-paced BCI walking simulator to complete a goal-oriented ambulation task. The operation of the proposed BCI system requires short training, is intuitive, and robust against participant-to-participant and day-to-day neurophysiological variations. These findings indicate that BCI-controlled lower extremity prostheses for gait rehabilitation or restoration after SCI may be feasible in the future. © 2013 King et al.; licensee BioMed Central Ltd.

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